1. Field of the Invention
The present invention relates to irrigation sprinklers and, more particularly, to an oscillating fan-jet sprinkler of the type which has a slowly oscillating horizontal nozzle cylinder with a row of jet nozzles arranged in a fantail pattern and which uses a water-driven turbine to produce the oscillating motion of the nozzle cylinder.
2. Description of the Prior Art
Various oscillating sprinklers of the type mentioned above are known from the prior art. They have received widespread use as residential lawn sprinklers and for the irrigation of vegetable and flower beds, having the advantageous feature of covering an area of generally rectangular outline.
It is also known to arrange in the drive mechanism of the oscillating sprinkler means by which the oscillation range of the nozzle cylinder can be increased or decreased and shifted in relation to the supporting plane of the sprinkler. Such an adjustment mechanism is suggested in U.S. Pat. No. 2,914,255. This publication discloses an oscillating lawn sprinkler featuring an oscillation drive whose horizontal output shaft has a crank on its extremity with a connecting link attached by its distal extremity to an arcuately slotted control sector. Depending upon the point along the arcuate slot of the control section at which the connecting link is attached, the oscillation range of the spray tube or nozzle cylinder is relatively larger or smaller and shifted to one side or the other of the vertical center plane of the sprinkler. Thus, it is possible to increase or decrease the length of the area which is being covered, as well as to shift the location of that area in relation to the position of the sprinkler.
A related solution to the problem of oscillation range adjustability involves the attachment of the distal extremity of the connecting link to the drive sector on the oscillating nozzle cylinder by means of a rotatable eccentric attachment member which, depending upon its orientation in relation to the connecting link, increases or decreases the distance of the latter from the axis of the nozzle cylinder, as well as the angular drive relationship between the output shaft and the nozzle cylinder. The result of this adjustability is again an increase or decrease of the oscillation range, coupled with an angular shift of this range to one side or the other of a vertical center plane. This mechanism is disclosed in U.S. Pat. No. 4,245,786, for example.
Both prior art devices have the common shortcoming that the adjustability of the angular position of the oscillation range is immutably coupled with an increase or decrease of the oscillation range. Furthermore, the arrangement of the adjustment means as part of a crank drive makes it necessary to arrange the crank drive on the outside of the sprinkler housing. In the case of the eccentric attachment member, the device requires an adjustment know with inscriptions, such as "full", "partial", "right" and "left", without which it would be extremely difficult to set the proper adjustment, without repeated prior trial and error. The need for inscriptions, on the other hand, requires differently inscribed parts for markets in countries of different language.